Turbopump having cooled shaft

ABSTRACT

A turbopump having an inducer and a two stage centrifugal pump has hydrogen entering an inducer and passing through a first stage impeller and a second stage stage impeller to the exit thereof. A turbine is located on the opposite side of said impellers from the inducer and has an integral shaft extending through the impellers and inducer on which they are mounted. A front radial bearing means is positioned between the inducer and first impeller and a thrust balancer means and rear radial bearing means are positioned between the second impeller and the turbine. An interstage seal extends between the two impellers. Hydrogen is taken from the hydrogen path to operate the axial thrust bearing and to cool the two radial bearings. Further, the hydrogen flow is taken from the inlet to the second stage impeller and directed through the shaft having a tortuous path therethrough to provide a desired cooling action. Dead air spaces are provided adjacent the turbine mounting to aid in the formation of a heat transfer barrier.

Stats tnt [191 Unite Sandy, J r.

[ 51 May 22, 1973 [75] Inventor: James J. Sandy, .112, Lake Park, Fla.

[73] Assignee: United Aircraft Corporation, East Hartford, Conn.

[22] Filed: May 24, 1971 [21] Appl. No.: 146,333

Primary Examiner-C. J. Husar Attorney-Jack N. McCarthy 5/1964 Shiley etal. ..417/901 X [57] ABSTRACT A turbopump having an inducer and a twostage centrifugal pump has hydrogen entering an inducer and passingthrough a first stage impeller and a second stage stage impeller to theexit thereof. A turbine is located on the opposite side of saidimpellers from the inducer and has an integral shaft extending throughthe impellers and inducer on which they are mounted. A front radialbearing means is positioned between the inducer and first impeller and athrust balancer means and rear radial bearing means are positionedbetween the second impeller and the turbine. An interstage seal extendsbetween the two impellers. Hydrogen is taken from the hydrogen path tooperate the axial thrust bearing and to cool the two radial bearings.

Further, the hydrogen flow is taken from the inlet to the second stageimpeller and directed through the shaft having a tortuous paththerethrough to provide a desired cooling action. Dead air spaces areprovided adjacent the turbine mounting to aid in the formation of a heattransfer barrier.

10 Claims, 3 Drawing Figures T Wm PAIENIE HLYZZIHYS SHEET 2 OF 3TURBOPUMP HAVING COOLED SHAFT BACKGROUND OF THE INVENTION This inventionrelates to a turbopump and its cooling means, and more particularly tothose turbopumps having a very hot turbine and a very cold pump.

SUMMARY OF INVENTION A primary object of the present invention is toprovide a tiebolt shaft concept that is also integral with the turbinedisk and which will operate under adverse environmental conditions.

In accordance with the present invention, a rotor assembly is formedwherein all of the rotating parts are assembled on a shaft integral witha turbine disk.

In accordance with a further aspect of the invention a turbopump isprovided having a shaft cooling system which can use the fluid beingpumped to properly cool and permit proper rotation of the shaft.

This invention includes a tortuous path of pumped fluid through theshaft of the turbopump and also including a dead gas chamber meansbetween the passageway extending through the shaft and the turbine disk.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing the frontportion of the turbopump; and

FIG. 1A is a view showing the rear portion of the turbopump.

FIG. 2 is a sectional view showing the transition section between therear bearing and turbine disk with isotherms.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 1A, theturbopump is made up of two main parts, the stationary housing 4 androtor assembly 6.

The rotor assembly 6, which comprises the rotating portion of theturbopump, is formed of eight main parts. These are (l) the inducer 8,(2) the mounting means for the inner race of the front bearing 1 1 andaccompanying inner seal members 7 and 9, (3) the first stage impeller12, (4) the inner seal member 14 of the interstage seal 15, (5 thesecond stage impeller 16, (6) the thrust piston 18 of the thrustbalancer, (7) the mounting means for the inner race 20 of the rearbearing 21 and accompanying inner seal members 17 and 19, and (8) theturbine assembly 22 and its integral shaft 24. Said shaft 24 extendsthrough all eight main parts and has a cap 26 affixed to its forwardfree end.

The cap 26 contacts the inducer 8 and is held on by a bolt 28.

The stationary housing 4, which comprises the stationary portion of theturbopump, is formed of eight main parts. These are (l) the casing 40forming the housing for the inducer 8, (2) the mounting means for theouter race 42 of the front bearing 11 and accompanying outer sealmembers 44 and 46, (3) the housing for the blades 89 of the first stageimpeller 12, 4) the outer seal member 48 of the interstage seal 15, 5)the housing for the blades 90 of the second stage impeller 16, (6) ahousing 50 for the thrust piston 18 of the thrust balancer, (7) themounting means for the outer race 52 of the rear bearing 21 andaccompanying outer seal members 54 and 56 and 8) the housing 58 whichincludes a passageway 61 into which blades 23 of the turbine assembly 22project. For ease of assembly of the rotor assembly 6 within thestationary housing 4, some main parts are constructed of a plurality ofcooperating smaller parts.

The rotor assembly 6 and stationary housing 4 cooperate in the followingmanner to produce a thermal transition section in the turbopump thatwill withstand large thermal gradients. The turbine disk 60 of theturbine assembly 22 is formed having the integral shaft 24 extendingforwardly thereof. Seal member 19 is mounted on integral shaft 24 andhas one side contacting the turbine disk 60. The inner seal member 19 isspaced from the forward face of the turbine disk 60 by an axiallyextending flange 62 and forms an annular chamber 64 with the turbinedisk, shaft 24 and flange 62. The inner seal member 19 includes annularsealing edges projecting outwardly from the rear of the seal member. Theinner race 20 of the rear bearing 21 is located on the shaft 24 adjacentthe seal member 19 and is positioned over a section having cooling slotsfor the passage of a cooling fluid.

The thrust piston 18 of the thrust balancer is made integral with andextends outwardly from a hollow shaft section 66 which has its rear endadjacent the forward end of the inner race 20. These two adjacent endshave cooling slots therebetween for the passage of a cooling fluid. Fordetails of the thrust balancer, see US. Pat. No. 3,485,541. The hollowshaft section 66 has internal splines 68 on an inwardly extendingcircular flange 70 at its rear end which engage splines 72 on shaft 24to insure like rotation of both parts. The forward part of the hollowshaft section 66 includes annular sealing edges projecting outwardly.The part of the hollow shaft section 66 forward of the flange 70 extendsto a point spaced radially inwardly from the inlet to the second stageimpeller 16 and forms an annular space with the shaft 24.

The second stage impeller 16 is mounted on the shaft 24 with arearwardly extending annular flange 74 extending into the annular spacejust referred to. An annular flange 76 located around flange 74 engagesthe forward end of the hollow shaft section 66. These mating ends havestepped sections which meet to position the two members axially andradially. The annular flange 74 forms a U-shaped passage with the hollowshaft section 66 and the shaft 24. The annular flange 74 has longsplines which engage mating long splines on the shaft 24. A space isprovided between the radial end of each spline and its cooperatingmember to permit a fluid to flow thereby for a purpose to be hereinafterdescribed. An annular flange 78 extends inwardly from the forward end ofannular flange 74 for abutment with the shaft 24. A plurality ofpassageways 80 extend through said flange 78. A plurality of passageways82 in flange 76 are arranged to cooperate with a plurality ofpassageways 84 in the mating free end of hollow shaft section 66.

The back of the second stage impeller 16 is spaced from the back of thefirst stage impeller 12. This is done by annular flanges 94 and 96 onthe impellers l6 and 12, respectively, which face each other and havespline means 98, therebetween. The inner seal member 14 of the innerstage seal is positioned above said projections 94 and 96 and is heldbetween the backs of the impellers l6 and 12.

The first stage impeller 12 is mounted on the shaft 24 by a mountingsleeve 102 on which is located the inner race and the inner seal members7 and 9. A flange 104 extends forwardly from the first stage impeller 12and has an outer facing radial surface and a forwardly facing axialsurface which engage an inner facing radial surface and a rearwardlyfacing axial surface, respectively. Downwardly extending projectionsfrom the end of the flange 104 engage rearwardly extending projectionsfrom the bottom of the mounting sleeve 102. The inner seal member 9includes annular sealing edges projecting outwardly from a flangelocated at the rear end of mounting sleeve 102. The inner race 10 of thefront bearing 11 is located on the mounting sleeve 102 adjacent anabutment on the sleeve. The abutment mating with the inner race 10 andthe portion of the sleeve under the inner race is formed having coolingslots. The seal member 7 is positioned with one side against the forwardend of the inner race 10. A forwardly extending flange extends from theouter edge thereof.

A nut member 106 is threaded onto the forward part of shaft 24 onthreads108 and tightened against the forward end of the mounted sleeve102 until it is properly torqued to hold the parts just enumerated intheir proper position.

The inducer 8 is then placed over the forward end of the shaft 24 havingan inner cylindrical member 110 which fits over the forward end of themounting sleeve 102 and engages the inner seal member 7. Splines on theinterior of member 110 engage mating splines on nut 106 and theforwardly projecting part of mounting sleeve 102. Another nut 112 ispivotally mounted on the forward end of shaft 24 to engage an inwardlyex-' tending flange 114 on the inducer 8 to fix it in place. Any lockingmeans may be used to fix the nut 112 in place. A cap 26 is then placedover an opening in the front of the inducer 8 to provide a smoothforward surface thereto. An annular chamber 116 is formed between theforward part of the shaft, the inducer 8 and the cap 26. A plurality ofopenings 118 extend from said chamber to the outer surface of said capfor a purpose to be hereinafter described.

The shaft 24 is formed as a hollow member. The forward part of the shaftincludes a long passageway 130 which extends to a point just below theinlet to the second stage impeller. From this point to the forward edgeof the rear bearing 21 a bore 132 is formed approximately twice thediameter of passageway 130. At this point, two enlarged cut-out annularsections 134 and 136 are formed which extend to the forward face of theturbine disk 60. These sections are separated by flange 138 extendinginwardly to a short cylindrical member 140.

A center tube member 150 is positioned within said opening 132 and saidportions 134 and 136. The forward part of the center tube is formed as apipe member 154 having an inner diameter equal to the diameter ofpassageway 130 while the rear part, extending across the cut-out annularsections 134 and 136, is formed having a cylindrical section 155 at itsforward end and a cylindrical section 156 at its rearward end. Saidsections are separated by a solid partition aligned with the shortcylindrical member 140. The forward end of the rear part of the centertube has a flange 160 thereon which engages a surface 161 at the end ofopening 132, the forward end of the rear part of the center tube has aflange 158 thereon which engages an opening through the center of theturbine disk 60, and the center section of the rear part of the centertube has a flange 164 thereon which engages the inner surface of thecylindrical member 140. Closure member 157 is fixed in the end of therear part of cylindrical section 156. The rearward end of the pipemember 154 is fixed within the forward part of the cylindrical sectionand the forward end of the pipe member 154 is fixed in the rearward endof the passageway 130. It can be seen that the cylindrical section 155,pipe member 154, and passageway 130 combine to form an elongatedpassageway.

A plurality of passageways extend radially through the shaft 24 from apoint just rearwardly of the flange 78 into the opening 132 and aplurality of passageways 174 extend radially through the shaft 24connecting chamber 116 to the forward part of passageway 130. The flange160 has a pluralityof openings 162 therein. A plurality of openingsconnect the rear end of cylindrical section 155 with the rear end of thecut-out annular section 134 and the forward end of cylindrical section156 has a plurality of passageways connecting it to the cut-out annularsection 136. It is noted that the cut-out section 136 forms a dead gaschamber with center tube member 150 and cylindrical section 156 forms adead gas chamber in view of the fixed end 157. A plurality of openings182 connect these dead gas chambers.

The stationary housing 4 as stated hereinbefore, is positioned aroundthe rotor assembly and with each part performing its function asintended with the mating portion from the rotor assembly. The casing 40includes a cylindrical inner surface 200 which engages the outer tips ofthe blade of the inducer 8 and a flange 202 is located at its forwardend for engagement with a flange 204 of a mating conduit 206 passinghydrogen to the turbopump.

The mounting means for the outer race 42 of the front bearing 11 andaccompanying outer seal members 44 and 46 comprise a plurality ofsupport members 210 which extend inwardly from the stationary housing toa point between the rear of the inducer and the forward part of theimpeller 12 to support an annular member 212. The outer surface of theannular member 212 forms the inner side of the passageway connecting theinducer to the first stage pump while the interior thereof hasdownwardly extending annular flange 214 which provides a surface for theseal member 46 and provides an abutment for one end of the outer race 42of the front bearing 11. Areas for permitting coolant flow engage theouter race 42. A washer member 216 is placed against the forward edge ofthe outer race 42 and an externally threaded nut 218 threadably engagesan internally threaded portion at the forward part of annular member212. A tab on the washer 216 extends into a groove on the washer to aidin locating it in place. The inner surface of the nut 218 provides themating seal surface for seal member 44.

A passageway 250 extends from a point adjacent the outlet of theimpeller 12 through the housing 4 and support members 210 to the outerrace 42 of the front bearing 11. A restrictor 252 is located in thepassageway 250 in the sections through the support members 210. Thefluid then flows around the outer race 42 and inner race 10 and axiallythrough its seal members and back into the inlet of the impeller 12. Therestrictor 252 is a supply orifice and sets the total flow around thefront bearing 11.

The portion of the housing cooperating with the first stage pump iscomposed of several parts and one is the annular flange 220 whichextends downwardly between the rear faces of the first stage pump andsecond stage pump. The inner surface of this flange 220 carries theouter seal member 48 of the inner stage seal for cooperating with theinner seal member 14.

The portion of the housing cooperating with the second stage pump isalso composed of a composite of parts and this is also true of theportion of the housing cooperating with the thrust piston 18 of thethrust balancer. The rear of the stationary housing 4 forms a housingwhich supports the outer seal member 54, an annular member 226 and anannular member 230.

Outer race 52 of the rear bearing 21 is fixedly mounted I on annularmember 226 between a nut, and an inwardly extending flange extendingfrom the member 226. An annular'member 230 is positioned at the end ofthe stationary housing 4 and holds the member 226 in place by aforwardly extending flange 232. An inner surface 234 on this member 230serves as one cooperating outer seal member for part of the inner sealmember 19 and the other part of seal member 56 carries a cooperatingsurface for cooperation with remaining sealing portion of inner sealmember 19.

A passageway (not shown) connects the outlet of the second stageimpeller 16 to an annulus 260. This annulus 260 is in turn connected toan annular space formed between the housing and the front portion ofmember 226. Said annulus is in turn connected to a forwardly facing partof the bearing 21. The flow into this area is also carried beneath theinner race 20 by the formation of the cooling passages around the innerrace. Another annulus is formed rearwardly of the inner race of thebearing 21 and is connected by passageways in the inner seal member 19to an annulus placed just back of the bearing. This annulus is connectedbetween the inner and outer seal members 19 and 56 to the first stage ofthe turbine. A restrictor 270 located in passageway 262 sets the totalflow through and around rear bearing 21.

The housing 58 is conventionally formed and provides the duct 61 for thehot gases flowing over the blades 23 of the turbine.

Hydrogen enters the turbopump from the conduit 206 at the inlet of theinducer 8, and then travels through the inducer into the first stageimpeller 12. The hydrogen is then increased in pressure through thefirst stage impeller and collected in the first stage manifold 300. Thehydrogen leaves the first stage manifold 300 through a diffuser and across-over tube (not shown) to the inlet of the second stage impeller16. At this point hydrogen as a coolant is bled off through passageways82 and 84 to cool the shaft.

This coolant flow travels radially inwardly through the passageways andthen rearwardly along the passageways formed by the shaft section 66 andannular flange 74 where it turns and goes forwardly through the splinedsection of annular flange 74 and shaft 24. At the annulus formed at theforward end of the splined section the flow is divided into two paths,one path continues to flow along the shaft forwardly under the first andsecond stage impellers to where it is discharged radially outwardlythrough passageways 310 which extend through the rearward part of themounting sleeve 102 and the spacing provided between the annular flange214 and the first stage impeller into the inlet of the first stageimpeller.

The other path flows radially through passageways into the opening 132around the pipe member 154 and then through openings 162 in flange 160into the annular chamber formed by the cut-out annular section 134 andthe rear part of the center tube member 150. The flow then passesradially inwardly through openings into the cylindrical section 155 ofthe rear part of the center tube member 150 where it flows through thepipe member 154 into passageway 130. The passageway 130 extends to theforward end of the shaft 24 and at this point the coolant flows radiallyoutwardly through the passageways 174 into the chamber 116. Passagewaysl 18 directs the coolant from chamber 1 16 into the inlet of inducer 8.

In a construction of a turbopump as set forth herein the flow of coolantpassing through the passageways 82 was made to be 0.2 pounds per secondand the flow through each of the paths starting at the annulus in frontof the splined sections of the flange 74 and shaft 24 was made to be 0.1pounds per second. The flow through and around the rear bearing was madeto be 0.65 pounds per second. These flows gave substantially theisotherms shown in FIG. 2 for normal operation. It is noted that theshaft 24 and turbine disk 60 in FIG. 2 are not cross-sectioned so thatthe isotherms may be readily seen. The isotherms shown connect liketemperatures on the shaft.

1 claim 1. A turbopump including in combination a pump section and aturbine section, said turbine section having a turbine disk forsupporting turbine blades, said disk having an integral shaft, said pumpsection having impeller means mounted on said shaft, bearing meanssupporting said shaft, a dead gas chamber being formed in said shaftadjacent said turbine disk, a passageway extending from said pumpsection for conveying a pumped fluid through and around the shaft to apoint near the dead gas chamber to maintain a proper thermalenvironment, said bearing means supporting said shaft comprising a frontbearing means located adjacent said pump section and a rear bearingmeans located near said turbine disk, means for directing a pumped fluidthrough and around said bearing means.

2. A turbopump as set forth in claim 1 wherein a first annular chamberis formed in said shaft at a location radially inwardly from said rearbearing means, said annular chamber forming a part of said passageway,said dead gas chamber being positioned between said first annularchamber and said disk.

3. A turbopump as set forth in claim 2 wherein said passageway has itsinlet connected to said pump section, said passageway extending fromsaid inlet to a second point adjacent said rear bearing means, saidpassageway extending from said second point in the opposite direction toa third point in the mid portion of the shaft, said passageway extendingradially inwardly from said third point to an annular passageway withinsaid shaft, said annular passageway directing its cooling fluid to saidfirst annular chamber.

4. A turbopump as set forth in claim 3 wherein said passageway having anopening for directing its flow of cooling fluid into said pump section.

5. A turbopump as set forth in claim 3 wherein an inducer means ismounted forwardly of said pump section, said inducer means beingconnected to said shaft, said passageway extending forwardly throughsaid shaft from said annular chamber, said passageway having an openingfor directing its flow of cooling fluid into said inducer means.

6. A turbopump as set forth in claim 2 wherein said shaft has a firstpassage therein, the end of said shaft fixed to said disk having anenlarged bore intersecting said passage, the end of said bore adjacentsaid disk having an enlarged cut-out section forming an annular space, acenter tube member fixed in said bore, said center tube member having asecond passage therein, the outer surface of said center tube adjacentsaid disk forming a closed annular chamber with said cut-out section,said outer surface of said center tube member also forming an annularpassage with said bore, said second passage cooperating with said firstpassage, openings in said center tube connecting said annular passagewith second passage, said annular passage, second passage, openings, andfirst passage forming part of said passageway.

7. A turbopump as set forth in claim 6 wherein the end of said centertube member under said closed annular chamber has a chamber therein.

8. A turbopump apparatus including in combination, a supply of coldfluid, a pump section for pumping cold fluid, a supply of hot fluid, aturbine section for receiving a hot fluid; said turbine section having aturbine disk for supporting turbine blades; said disk having an integralshaft; said pump section having impeller means mounted on said shaft;shaft bearing means supporting said shaft; means between said impellermeans and turbine disk for maintaining a proper thermal environment,said last named means including: a dead gas chamber formed in said shaftadjacent said turbine disk, a second chamber formed in said shaftadjacent said first dead gas chamber, a first passageway extending fromsaid pump section for conveying the pump cold fluid around the shaft ata point near the first dead gas chamber, a second passageway extendingfrom said pump section for conveying the cold pump fluid through theshaft and through said second chamber adjacent the dead gas chamber,said shaft bearing means including bearing means located near saidturbine disk, means for directing the cold pumped fluid through saidbearing means.

9. A turbopump as set forth in claim 8 wherein a third passagewayextends from said second chamber to said pump section to return the coldpumped fluid back to the pump.

10. A turbopump as set forth in claim 8 wherein said hot fluid reachestemperatures over 1,000R and the cold fluid in said second chamberencounters temperatures in the order of R.

1. A turbopump including in combination a pump section and a turbinesection, said turbine section having a turbine disk for supportingturbine blades, said dIsk having an integral shaft, said pump sectionhaving impeller means mounted on said shaft, bearing means supportingsaid shaft, a dead gas chamber being formed in said shaft adjacent saidturbine disk, a passageway extending from said pump section forconveying a pumped fluid through and around the shaft to a point nearthe dead gas chamber to maintain a proper thermal environment, saidbearing means supporting said shaft comprising a front bearing meanslocated adjacent said pump section and a rear bearing means located nearsaid turbine disk, means for directing a pumped fluid through and aroundsaid bearing means.
 2. A turbopump as set forth in claim 1 wherein afirst annular chamber is formed in said shaft at a location radiallyinwardly from said rear bearing means, said annular chamber forming apart of said passageway, said dead gas chamber being positioned betweensaid first annular chamber and said disk.
 3. A turbopump as set forth inclaim 2 wherein said passageway has its inlet connected to said pumpsection, said passageway extending from said inlet to a second pointadjacent said rear bearing means, said passageway extending from saidsecond point in the opposite direction to a third point in the midportion of the shaft, said passageway extending radially inwardly fromsaid third point to an annular passageway within said shaft, saidannular passageway directing its cooling fluid to said first annularchamber.
 4. A turbopump as set forth in claim 3 wherein said passagewayalso extends axially from said third point to a fourth point adjacentsaid front bearing means, said passageway having an opening fordirecting its flow of cooling fluid into said pump section.
 5. Aturbopump as set forth in claim 3 wherein an inducer means is mountedforwardly of said pump section, said inducer means being connected tosaid shaft, said passageway extending forwardly through said shaft fromsaid annular chamber, said passageway having an opening for directingits flow of cooling fluid into said inducer means.
 6. A turbopump as setforth in claim 2 wherein said shaft has a first passage therein, the endof said shaft fixed to said disk having an enlarged bore intersectingsaid passage, the end of said bore adjacent said disk having an enlargedcut-out section forming an annular space, a center tube member fixed insaid bore, said center tube member having a second passage therein, theouter surface of said center tube adjacent said disk forming a closedannular chamber with said cut-out section, said outer surface of saidcenter tube member also forming an annular passage with said bore, saidsecond passage cooperating with said first passage, openings in saidcenter tube connecting said annular passage with second passage, saidannular passage, second passage, openings, and first passage formingpart of said passageway.
 7. A turbopump as set forth in claim 6 whereinthe end of said center tube member under said closed annular chamber hasa chamber therein.
 8. A turbopump apparatus including in combination, asupply of cold fluid, a pump section for pumping cold fluid, a supply ofhot fluid, a turbine section for receiving a hot fluid; said turbinesection having a turbine disk for supporting turbine blades; said diskhaving an integral shaft; said pump section having impeller meansmounted on said shaft; shaft bearing means supporting said shaft; meansbetween said impeller means and turbine disk for maintaining a properthermal environment, said last named means including: a dead gas chamberformed in said shaft adjacent said turbine disk, a second chamber formedin said shaft adjacent said first dead gas chamber, a first passagewayextending from said pump section for conveying the pump cold fluidaround the shaft at a point near the first dead gas chamber, a secondpassageway extending from said pump section for conveying the cold pumpfluid through the shaft and through said second chamber adjacent thedead gas chamber, said shaft bearing means including beAring meanslocated near said turbine disk, means for directing the cold pumpedfluid through said bearing means.
 9. A turbopump as set forth in claim 8wherein a third passageway extends from said second chamber to said pumpsection to return the cold pumped fluid back to the pump.
 10. Aturbopump as set forth in claim 8 wherein said hot fluid reachestemperatures over 1,000*R and the cold fluid in said second chamberencounters temperatures in the order of 100*R.